An imaging method and device is provided for inspecting for the presence, in an object like a wafer, of enclosed structures, such as vias, employing: an imaging sensor; an optical imager able to produce, on the imaging sensor, an object image in a field of view; and an illuminator for generating an illuminating beam and lighting the field of view in reflection, including: acquiring a first image of the object by illuminating the object with a first illuminating beam adapted to the object, such that the light of the beam penetrates the object; acquiring a second image of the object by illuminating the object with a second illuminating beam adapted to the object, such that the light of the beam is reflected by the surface of the object; and comparing the first and second images to identify structures that appear in the first image but not in the second image.
